Commercial waste, industrial waste, domestic waste etc., e. g. (hard) plastics, textiles, composites, rubber or waste wood (such as pallets and chipboards) need to be shredded before their ultimate disposal or particularly before they are recycled. For the shredding above all single-shaft or multi-shaft shredders are known from the prior art, which are charged with material, for instance, by wheel loaders, fork trucks or conveyor belts via a hopper
A conventional shredder comprises a rotor unit including a rotor, which is equipped with severing hooks or cutting blades, which may be provided, for instance, with concavely ground circular cutting crowns. The cutting blades are, for instance, screwed to cutting blade holders, which may be welded into or, for instance, be screwed to cutting blade pockets, which are milled into the rotor. The shredding of the charged material is accomplished between the cutting blades rotating with the rotor and stationary, i.e. non-rotating counter blades (stator blades, wiper elements). Typically, the rotor unit is driven outside the machine casing of the shredder into which the rotor unit is fitted.
Moreover, a conventional shredder may comprise a pushing device, by means of which the charged material is pushed in the direction of the rotating rotor. After the shredding between the rotating cutting blades and the counter blades the material is discharged by a screening device, which determines the shredding factor according to the screen size, and is transported further by means of a conveyor belt, a screw conveyor, a chain conveyor or a suction apparatus etc.
Examples for industrial shredders are the primary shredder JUPITER of the company Lindner Recyclingtech, which is a slowly operated single-shaft shredder mainly used for pre-shredding materials such as household refuse, commercial and industrial waste, the secondary shredder KOMET of the company Lindner Recylingtech, which is a single-shaft shredder particularly used for the secondary size reduction/granulation of pre-shredded material free from foreign particles, e.g. paper, cardboard packagings, plastic and foam materials, and the slowly operated single-shaft shredders UNIVERSO, MICROMAT and VEGA of the company Lindner Recyclingtech.
The machine casings of conventional shredders serve to accommodate the attachments and built-in components, like those of the cutting blade rotor and the drive components. During their operation they are subjected to great loads, especially in the form of vibrations. Therefore, the machine casings are provided in the form of welded casings. However, the required large-surface welding assembly groups involve the problem caused by a welding distortion, which renders the maintenance of dimensional tolerances difficult and may result in mechanical weak points. The effort for minimizing the welding distortion and for a correspondingly necessary post-processing is great. Therefore, it is the object to provide an alternative production method for a machine casing for a shredder that does not involve the welding distortion problem.